Spark-gage.



F. B. GRAHAM.

SPARK GAGE.

APPLICATION FILED NOV. 16. 1915.

Patented May 7, 1918.

BB Cimzham Inventor Witnesses Attorneys FRANK Iii GRAHAM, OF LANSING, MICHIGAN.

SPARK-GAGE.

Specification of Letters Patent.

Patented May 7, 1918.

Application filed November 16, 1916. Serial No. 131,739.

To all whom, it may concern.-

Be it known that I, FRANK B. GRAHAM, a citizen. of the United States, residin at Lansing, in the county of Ingham and tate of Michigan, have'invented a new and useful Spark-Gage, of which the following is a specification. p p

Thepresent invention relates to a spark gage for testing spark plugs of internal combustion engines, and it is the object of the invention to provide a novel and improved device of that character, which is simple and compact in construction, which can be readily carried about and conveniently applied to various spark plugs and which is practical, convenient and eflicient in use.

With the foregoing and other objects in View which-will appear as the description proceeds, the invention resides in the combinationand arrangement of parts and in the details of construction hereinafter described and claimed, it being understood that changes in the precise embodiment of the invention herein disclosed, can be made within the scope of what is claimed, without departing from the spirit of the invention.

The invention is illustrated in the accompanying drawing, wherein Figure 1 is a side elevation of the device,

as in use.

Fig. 2 is a longitudinal sect'o of the device, portions being shown in ele' ation.

The device embodies an elongated body 1 of hard rubber or other suitable insulating material, provided adjacent to one end with a cylindrical enlargement 2 having its axis,

disposed transversely. Said enlargement'2 has a laterally opening chamber or recess 3, and the body 1 is provided with alongitudinal or axial bore 4 extending from end to end and intersecting the recess 3.

A metallic pin or rpd 5 extends snugly through the longest p rtion of the bore 4' and has one terminallprojecting from the respective end of the body 1 and pointed, as at 6, to engage the cylinder of an internal combustion engine, whereby'to ground the pin 5 to the engine. The other terminal of the pin 5 projects within the recess 3 and has an electrode 7 fitted therein and projecting therefrom.

A second straight pin or rod of shorter servation.

length than the straight pin 5 extends snugly through the other portion of the bore 4 and projects into the recess 3,.being provided with an electrode 9 fitted within the inner end of the pin 8, there being. a spark gap between the two electrodes. A metallic cap 10 is fitted upon that end of the body 1 near which the enlargement 2 is located, and the pin 8 has itsouter end secured in any suitable manner to the cap 10, whereby to connect them electrically. The rim of the cap 10 overlaps the sides of the body 1, whereby when the point 6 is placed upon a cylinder, the body 1 canbe tilted to bring the ed e or 'rim of the cap 10 against the spar plug, as seen in Fig. 1, with the body '1 ,in any angular position about its axis. The spark age can thus be conveniently applied to various spark plugs. The body 1 as an annular rabbet 11 sur rounding the mouth of the recess 3. in which a glass panel or disk 12 is fitted to rotect the electrodes, and to expose them or ob- When the device is applied to the spark plug the sparks in jumping across the spark gap between the electrodes 7 and -9, will indicate that the'current is flowing between the spark plug andthe respective cylinder to ground, thus enabling the spark plugsof the various cylinders to be tested. quickly and conveniently. A v

. Having thus described the invention, what is claimed as new is A; sparkgage embodying an elongated member of insulating material having a laterally opening recess 1 and an axial longitudinal bore extending from end to end and intersecting said recess, straight pins extending. through the two portions of the bore and provided with spaced electrodes within said recess, one'pin having a terminal projecting-beyond one end of the body and pointed, and a metallic cap fitted upon and surrounding the other end of the body and attached to the other pin.-

. In testimony that I claim the foregoing as my own, I have hereto afiixed my signature in the presence of two witnesses.

d FRANK B. GRAHAM. I

Witnesses:

.DAN STEWART, H. A. PALMER. 

